1. Field of the Invention
The present invention relates generally to the field of upwardly-acting overhead doors, and more particularly to an improved roller assembly intended for use on a vehicularly-mounted door structure.
2. Description of the Prior Art
Upwardly-acting overhead door structures are commonplace. They are often found on garages and on truck bodies. Such vehicularly-mounted doors are subject to severe vibrational loading, as from road conditions and repeated starting and stopping of the vehicle. At the same time, such truck doors, particularly those on beverage trucks, are typically provided with lettering or advertising logos and decals. Applicant has observed that such lettering and decals often become misaligned because one door panel has shifted laterally relative to a vertically-adjacent door panel.
Thus, the problem faced by applicant was to provide an improved door structure for such vehicular applications, which would reduce, if not eliminate, such lettering and decal misalignment.
Unfortunately, an apparent solution to this problem was not foreshadowed by the prior art. Early attempts at a solution have included the provision of an additional interdigital hinge section to prevent lateral shifting of one panel relative to another. However, this was an item of extra cost, and required the provision of rivet heads, which themselves provided an obstacle to placement of such decals. At the same time, it has been felt desirable to extrude the door panels with integral hinge sections.
The roller members for such truck-mounted overhead doors have typically been mounted on slidable shafts which are laterally shiftable, as typically shown in U.S. Pat. No. 3,416,589.